Phenyl triazole derivative and its use for modulating the GABAA receptor complex

ABSTRACT

This invention relates to a novel phenyl triazole derivative, pharmaceutical compositions containing this compound, and methods of treatment therewith. The compound of the invention is in particular considered useful for the treatment of central nervous system diseases and disorders which are responsive to modulation of GABA A  receptors containing the α5 subunit.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Phase of PCT International ApplicationNo. PCT/EP2013/063193, filed on Jun. 25, 2013, which claims priorityunder 35 U.S.C. 119(e) to U.S. Provisional Application No. 61/664,287,filed on Jun. 26, 2012, and under 35 U.S.C. 119(a) to Patent ApplicationNo. PA201270368, filed in Denmark on Jun. 26, 2012, all of which arehereby expressly incorporated by reference into the present application.

TECHNICAL FIELD

This invention relates to a novel phenyl triazole derivative,pharmaceutical compositions containing this compound, and methods oftreatment therewith. The compound of the invention is in particularconsidered useful for the treatment of central nervous system diseasesand disorders which are responsive to modulation of GABA_(A) receptorscontaining the α5 subunit.

BACKGROUND ART

The GABA_(A) receptor protein complex is the molecular target of anumber of ligands, including the benzodiazepine class of tranquilizerdrugs. Multiple isoforms of the GABA_(A) receptor exist; each receptoris a pentameric complex comprising subunits drawn from α₁₋₆, β₁₋₃, γ₁₋₃,δ, ε, and θ subunit isoforms. However, the classical benzodiazepinesshow no subtype selectivity. Moreover it is believed that one of the keyelements responsible for the drawbacks of the classical benzodiazepanes(such as sedation, dependency and cognitive impairment) has to do withthe α1 subunit of the GABA_(A) receptors.

Further, it has been suggested that the GABA_(A) α5 subunit represents atherapeutic target for treatment of various diseases and disorders ofthe central nervous system, and literature has establish a nexus betweenthe GABA_(A) α5 subunit as therapeutic target, and various acute andchronic neurological disorders, chronic neurological disorders,cognitive disorders, Alzheimer's disease, memory deficits,schizophrenia, positive, negative and/or cognitive symptoms associatedwith schizophrenia, bipolar disorders, autism, Down syndrome,neurofibromatosis type I, sleep disorders, disorders of circadianrhythms, amyotrophic lateral sclerosis, dementia caused by AIDS,psychotic disorders, substance-induced psychotic disorder, anxietydisorders, generalized anxiety disorder, panic disorder, delusionaldisorder, obsessive compulsive disorders, acute stress disorder, drugaddictions, movement disorders, Parkinson's disease, restless legsyndrome, cognition deficiency disorders, multi-infarct dementia, mooddisorders, depression, neuropsychiatric conditions, psychosis,attention-deficit hyperactivity disorder, neuropathic pain, stroke,attentional disorders, eating disorders, anorexia, anorexia nervosa,cachexia, weight loss, muscle atrophy, pain conditions, chronic pain,nociceptive pain, post-operative pain, osteoarthritis pain, rheumatoidarthritis pain, musculoskeletal pain, burn pain, ocular pain, pain dueto inflammation, pain due to bone fracture, hyperalgesia, neuropathicpain, herpes-related pain, HIV-related neuropathic pain, traumatic nerveinjury, post-stroke pain, post-ischemia pain, fibromyalgia, chronicheadache, migraine, tension-type headache, diabetic neuropathic pain,phantom limb pain, visceral pain and cutaneous pain, and compoundscapable of modulating GABA_(A) receptors containing the α5 subunit arein particular expected to be useful candidates for the treatment of i.a.cognitive disorders, Alzheimer's disease, schizophrenia, positive,negative and/or cognitive symptoms associated with schizophrenia, andcognitive deficits associated with Down syndrome, with autism, withneurofibromatosis type I, or after stroke.

Isoxazole derivatives capable of modulating the GABA_(A) receptorcomplex are known from e.g. WO 2007/039389, WO 2007/042420, WO2007/054444, WO 2007/071598, WO 2007/074078, WO 2007/074089, WO2007/137954, WO 2009/000662, WO 2009/071464, WO 2009/071476, WO2009/071477, WO 2010/097368, WO 2010/112475, WO 2010/125042, WO2010/127968, WO 2010/127974, WO 2010/127975, WO 2010/127976 and WO2010/127978, and triazole derivatives capable of modulating the GABA_(A)receptor complex are known from e.g. WO 2012/062687. Moreover WO2008/025539, WO 2008/025540, WO 2009/149795 and WO 2011/020615 describeheterocyclic compounds, including certain phenyl triazole derivatives,useful as agonists of the NR1 H4 (FXR) receptor. However, the triazolederivatives of the present invention have not been reported.

SUMMARY OF THE INVENTION

In its first aspect, the invention provides a phenyl triazole derivativeof the following structure (I):

i.e.1-[6-[[5-(2-fluorophenyl)-3-methyl-triazol-4-yl]methoxy]-3-pyridyl]imidazole-4-carbonitrile,and pharmaceutically acceptable salts thereof.

In its second aspect, the invention provides a pharmaceuticalcomposition, comprising a therapeutically effective amount of the phenyltriazole derivative of formula (I) of the invention, or apharmaceutically acceptable salt thereof, together with at least onepharmaceutically acceptable carrier, excipient or diluent.

In a further aspect, the invention relates to the use of the phenyltriazole derivative of formula (I) of the invention, or apharmaceutically acceptable salt thereof, for the manufacture of apharmaceutical composition for the treatment, prevention or alleviationof a disease or a disorder or a condition of a mammal, including ahuman, which disease, disorder or condition is responsive to modulationof GABA_(A) receptors containing the α5 subunit.

In a still further aspect, the invention provides a method fortreatment, prevention or alleviation of a disease or a disorder or acondition of a living animal body, including a human, which disorder,disease or condition is responsive to modulation of GABA_(A) receptorscontaining the α5 subunit, which method comprises the step ofadministering to such a living animal body in need thereof atherapeutically effective amount of the phenyl triazole derivative offormula (I) of the invention, or a pharmaceutically acceptable saltthereof.

Other objects of the invention will be apparent to the person skilled inthe art from the following detailed description and examples.

DETAILED DISCLOSURE OF THE INVENTION Phenyl Triazole Derivatives

In its first aspect the present invention provides a phenyl triazolederivative of the following structure (I):

i.e.1-[6-[[5-(2-fluorophenyl)-3-methyl-triazol-4-yl]methoxy]-3-pyridyl]imidazole-4-carbonitrile;

or a pharmaceutically acceptable salt thereof.

Pharmaceutically Acceptable Salts

The phenyl triazole derivative of formula (I) of the invention may beprovided in any form suitable for the intended administration. Suitableforms include pharmaceutically (i.e. physiologically) acceptable saltsof the compound of the invention.

Examples of pharmaceutically acceptable salts include, withoutlimitation, the non-toxic inorganic and organic acid addition salts suchas the hydrochloride derived from hydrochloric acid, the hydrobromidederived from hydrobromic acid, the nitrate derived from nitric acid, theperchlorate derived from perchloric acid, the phosphate derived fromphosphoric acid, the sulphate derived from sulphuric acid, the formatederived from formic acid, the acetate derived from acetic acid, theaconate derived from aconitic acid, the ascorbate derived from ascorbicacid, the benzenesulphonate derived from benzensulphonic acid, thebenzoate derived from benzoic acid, the cinnamate derived from cinnamicacid, the citrate derived from citric acid, the embonate derived fromembonic acid, the enantate derived from enanthic acid, the fumaratederived from fumaric acid, the glutamate derived from glutamic acid, theglycolate derived from glycolic acid, the lactate derived from lacticacid, the maleate derived from maleic acid, the malonate derived frommalonic acid, the mandelate derived from mandelic acid, themethanesulphonate derived from methane sulphonic acid, thenaphthalene-2-sulphonate derived from naphtalene-2-sulphonic acid, thephthalate derived from phthalic acid, the salicylate derived fromsalicylic acid, the sorbate derived from sorbic acid, the stearatederived from stearic acid, the succinate derived from succinic acid, thetartrate derived from tartaric acid, the toluene-p-sulphonate derivedfrom p-toluene sulphonic acid, and the like. Such salts may be formed byprocedures well known and described in the art.

Such pharmaceutically acceptable salts and common methodology forpreparing them are known in the art. Further details may be found inStahl P et al, Handbook of Pharmaceutical Salts: Properties, Selectionand Use; Wiley-VCH, 2002.

In addition, the phenyl triazole derivative of formula (I) of theinvention may exist in the form of a polymorph, or the compound may beprovided in dissoluble or indissoluble forms together with apharmaceutically acceptable solvent such as water, ethanol, and thelike. Dissoluble forms may also include hydrated forms such as themonohydrate, the dihydrate, the hemihydrate, the trihydrate, thetetrahydrate, and the like. In general, the dissoluble forms areconsidered equivalent to indissoluble forms for the purposes of thisinvention.

Labelled Compounds

The phenyl triazole derivative of formula (I) of the invention may beused in its labelled or unlabelled form. In the context of thisinvention a labelled compound has one or more atoms replaced by an atomhaving an atomic mass or mass number different from the atomic mass ormass number usually found in nature. The labelling will allow easyquantitative detection of said compound.

The labelled compounds of the invention may be useful as diagnostictools, radio tracers, or monitoring agents in various diagnosticmethods, and for in vivo receptor imaging.

The labelled isomer of the invention preferably contains at least oneradionuclide as a label. Positron emitting radionuclides are allcandidates for usage. In the context of this invention the radionuclideis preferably selected from ²H (deuterium), ³H (tritium), ¹¹C, ¹³C, ¹⁴C,¹³¹I, ¹²⁵I, ¹²³I and ¹⁸F.

The physical method for detecting the labelled isomer of the presentinvention may be selected from Position Emission Tomography (PET),Single Photon Imaging Computed Tomography (SPECT), Magnetic ResonanceSpectroscopy (MRS), Magnetic Resonance Imaging (MRI), and Computed AxialX-ray Tomography (CAT), or combinations thereof.

Deuterated Analogs

The phenyl triazole derivative of formula (I) of the invention may beprovided in the form of their deuterated analogs. Deuterium forms bondswith carbon that vibrate at a lower frequency and are thus stronger thanC—H bonds. Therefore “heavy hydrogen” (deuterium) versions of drugs maybe more stable towards degradation and last longer in the organism.

Methods of Preparation

The phenyl triazole derivative of formula (I) of the invention may beprepared by conventional methods for chemical synthesis, e.g. thosedescribed in the working examples. The starting materials for theprocess described in the present application are known or may readily beprepared by conventional methods from commercially available chemicals.

The end product of the reactions described herein may be isolated byconventional techniques, e.g. by extraction, crystallisation,distillation, chromatography, etc.

Biological Activity

The phenyl triazole derivative of formula (I) of the invention arecapable of modulating GABA_(A) receptors containing the α5 subunit. Thusin further aspect, the phenyl triazole derivative of formula (I) of theinvention is considered useful for the treatment, prevention oralleviation of a disease, disorder or condition responsive to modulationof GABA_(A) receptors containing the α5 subunit, in particular in thecentral nervous system.

In one embodiment, the phenyl triazole derivative of formula (I) of theinvention is considered useful for the treatment, prevention oralleviation of a disease, disorder or condition which is selected fromthe group of acute neurological disorders, chronic neurologicaldisorders, cognitive disorders, Alzheimer's disease, memory deficits,schizophrenia, positive, negative and/or cognitive symptoms associatedwith schizophrenia, bipolar disorders, autism, Down syndrome,neurofibromatosis type I, sleep disorders, disorders of circadianrhythms, amyotrophic lateral sclerosis (ALS), dementia caused by AIDS,psychotic disorders, substance-induced psychotic disorder, anxietydisorders, generalized anxiety disorder, panic disorder, delusionaldisorder, obsessive compulsive disorders, acute stress disorder, drugaddictions, movement disorders, Parkinson's disease, restless legsyndrome, cognition deficiency disorders, multi-infarct dementia, mooddisorders, depression, neuropsychiatric conditions, psychosis,attention-deficit hyperactivity disorder, neuropathic pain, stroke,attentional disorders, and for use as cognitive enhancers.

In another embodiment, the phenyl triazole derivative of formula (I) ofthe invention is considered useful for the treatment, prevention oralleviation of a disease, disorder or condition which is selected fromthe group of eating disorders, anorexia, anorexia nervosa, cachexia,weight loss, muscle atrophy, pain conditions, chronic pain, nociceptivepain, post-operative pain, osteoarthritis pain, rheumatoid arthritispain, musculoskeletal pain, burn pain, ocular pain, pain due toinflammation, pain due to bone fracture, hyperalgesia, neuropathic pain,herpes-related pain, HIV-related neuropathic pain, traumatic nerveinjury, post-stroke pain, post-ischemia pain, fibromyalgia, chronicheadache, migraine, tension-type headache, diabetic neuropathic pain,phantom limb pain, visceral pain and cutaneous pain.

In a third embodiment, the phenyl triazole derivative of formula (I) ofthe invention is considered useful for the treatment, prevention oralleviation of a disease, disorder or condition selected from the groupof cognitive disorders, Alzheimer's disease, schizophrenia, positive,negative and/or cognitive symptoms associated with schizophrenia, andcognitive deficits associated with Down syndrome, with autism, withneurofibromatosis type I, or after stroke.

In a fourth embodiment, the phenyl triazole derivative of formula (I) ofthe invention is considered useful for the treatment, prevention oralleviation of a disease, disorder or condition selected from the groupof Alzheimer's disease, schizophrenia and Down syndrome.

In a fifth embodiment, the phenyl triazole derivative of formula (I) ofthe invention is considered useful as a cognitive enhancer.

Further, the phenyl triazole derivative of formula (I) of the inventionmay be useful as a radioligand in assays for detecting compounds capableof modulating GABA_(A) receptors containing the α5 subunit.

It is at present contemplated that a suitable dosage of the activepharmaceutical ingredient (API), that is the compound of formula (I) ora pharmaceutically acceptable salt thereof, including solvates andanhydrates, is within the range of from about 0.1 to about 1000 mg APIper day, more preferred of from about 10 to about 500 mg API per day,most preferred of from about 30 to about 100 mg API per day, dependent,however, upon the exact mode of administration, the form in which it isadministered, the indication considered, the subject and in particularthe body weight of the subject involved, and further the preference andexperience of the physician or veterinarian in charge.

Pharmaceutical Compositions

In another aspect the invention provides novel pharmaceuticalcompositions comprising a therapeutically effective amount of the phenyltriazole derivative of formula (I) of the invention.

While the phenyl triazole derivative of formula (I) of the invention foruse in therapy may be administered in the form of the raw chemicalcompound, it is preferred to introduce the active ingredient, optionallyin the form of a physiologically acceptable salt, in a pharmaceuticalcomposition together with one or more adjuvants, excipients, carriers,buffers, diluents, and/or other customary pharmaceutical auxiliaries.

In a preferred embodiment, the invention provides pharmaceuticalcompositions comprising the phenyl triazole derivative of formula (I) ofthe invention, or a pharmaceutically acceptable salt or derivativethereof, together with one or more pharmaceutically acceptable carriers,and, optionally, other therapeutic and/or prophylactic ingredients,known and used in the art. The carrier(s) must be “acceptable” in thesense of being compatible with the other ingredients of the formulationand not harmful to the recipient thereof.

Pharmaceutical compositions of the invention may be those suitable fororal, rectal, bronchial, nasal, pulmonal, topical (including buccal andsub-lingual), transdermal, vaginal or parenteral (including cutaneous,subcutaneous, intramuscular, intraperitoneal, intravenous,intraarterial, intracerebral, intraocular injection or infusion)administration, or those in a form suitable for administration byinhalation or insufflation, including powders and liquid aerosoladministration, or by sustained release systems. Suitable examples ofsustained release systems include semipermeable matrices of solidhydrophobic polymers containing the compound of the invention, whichmatrices may be in form of shaped articles, e.g. films or microcapsules.

The phenyl triazole derivative of formula (I) of the invention, togetherwith a conventional adjuvant, carrier, or diluent, may thus be placedinto the form of pharmaceutical compositions and unit dosages thereof.Such forms include solids, and in particular tablets, filled capsules,powder and pellet forms, and liquids, in particular aqueous ornon-aqueous solutions, suspensions, emulsions, elixirs, and capsulesfilled with the same, all for oral use, suppositories for rectaladministration, and sterile injectable solutions for parenteral use.Such pharmaceutical compositions and unit dosage forms thereof maycomprise conventional ingredients in conventional proportions, with orwithout additional active compounds or principles, and such unit dosageforms may contain any suitable effective amount of the active ingredientcommensurate with the intended daily dosage range to be employed.

The phenyl triazole derivative of formula (I) of the present inventioncan be administered in a wide variety of oral and parenteral dosageforms. It will be obvious to those skilled in the art that the followingdosage forms may comprise, as the active component, either a compound ofthe invention or a pharmaceutically acceptable salt of a compound offormula (I) of the invention.

For preparing pharmaceutical compositions from a phenyl triazolederivative of formula (I) of the present invention, pharmaceuticallyacceptable carriers can be either solid or liquid. Solid formpreparations include powders, tablets, pills, capsules, cachets,suppositories, and dispersible granules. A solid carrier can be one ormore substances which may also act as diluents, flavouring agents,solubilizers, lubricants, suspending agents, binders, preservatives,tablet disintegrating agents, or an encapsulating material.

In powders, the carrier is a finely divided solid, which is in a mixturewith the finely divided active component.

In tablets, the active component is mixed with the carrier having thenecessary binding capacity in suitable proportions and compacted in theshape and size desired.

The powders and tablets preferably contain from five or ten to aboutseventy percent of the active compound. Suitable carriers are magnesiumcarbonate, magnesium stearate, talc, sugar, lactose, pectin, dextrin,cellulose, starch, gelatin, tragacanth, methylcellulose, sodiumcarboxymethylcellulose, a low melting wax, cocoa butter, and the like.The term “preparation” is intended to include the formulation of theactive compound with encapsulating material as carrier providing acapsule in which the active component, with or without carriers, issurrounded by a carrier, which is thus in association with it.Similarly, cachets and lozenges are included. Tablets, powders,capsules, pills, cachets, and lozenges can be used as solid formssuitable for oral administration.

For preparing suppositories, a low melting wax, such as a mixture offatty acid glyceride or cocoa butter, is first melted and the activecomponent is dispersed homogeneously therein, as by stirring. The moltenhomogenous mixture is then poured into convenient sized moulds, allowedto cool, and thereby to solidify.

Compositions suitable for vaginal administration may be presented aspessaries, tampons, creams, gels, pastes, foams or sprays containing inaddition to the active ingredient such carriers as are known in the artto be appropriate.

Liquid preparations include solutions, suspensions, and emulsions, forexample, water or water-propylene glycol solutions. For example,parenteral injection liquid preparations can be formulated as solutionsin aqueous polyethylene glycol solution.

The compound according to the present invention may thus be formulatedfor parenteral administration (e.g. by injection, for example bolusinjection or continuous infusion) and may be presented in unit dose formin ampoules, pre-filled syringes, small volume infusion or in multi-dosecontainers with an added preservative. The compositions may take suchforms as suspensions, solutions, or emulsions in oily or aqueousvehicles, and may contain formulation agents such as suspending,stabilising and/or dispersing agents. Alternatively, the activeingredient may be in powder form, obtained by aseptic isolation ofsterile solid or by lyophilization from solution, for constitution witha suitable vehicle, e.g. sterile, pyrogen-free water, before use.

Aqueous solutions suitable for oral use can be prepared by dissolvingthe active component in water and adding suitable colorants, flavours,stabilising and thickening agents, as desired.

Aqueous suspensions suitable for oral use can be made by dispersing thefinely divided active component in water with viscous material, such asnatural or synthetic gums, resins, methylcellulose, sodiumcarboxymethylcellulose, or other well known suspending agents.

Also included are solid form preparations, intended for conversionshortly before use to liquid form preparations for oral administration.Such liquid forms include solutions, suspensions, and emulsions. Inaddition to the active component such preparations may comprisecolorants, flavours, stabilisers, buffers, artificial and naturalsweeteners, dispersants, thickeners, solubilizing agents, and the like.

For topical administration to the epidermis the compound of theinvention may be formulated as ointments, creams or lotions, or as atransdermal patch. Ointments and creams may, for example, be formulatedwith an aqueous or oily base with the addition of suitable thickeningand/or gelling agents. Lotions may be formulated with an aqueous or oilybase and will in general also contain one or more emulsifying agents,stabilising agents, dispersing agents, suspending agents, thickeningagents, or colouring agents.

Compositions suitable for topical administration in the mouth includelozenges comprising the active agent in a flavoured base, usuallysucrose and acacia or tragacanth; pastilles comprising the activeingredient in an inert base such as gelatin and glycerine or sucrose andacacia; and mouthwashes comprising the active ingredient in a suitableliquid carrier.

Solutions or suspensions are applied directly to the nasal cavity byconventional means, for example with a dropper, pipette or spray. Thecompositions may be provided in single or multi-dose form.

Administration to the respiratory tract may also be achieved by means ofan aerosol formulation in which the active ingredient is provided in apressurised pack with a suitable propellant such as a chlorofluorocarbon(CFC) for example dichlorodifluoromethane, trichlorofluoromethane, ordichlorotetrafluoroethane, carbon dioxide, or other suitable gas. Theaerosol may conveniently also contain a surfactant such as lecithin. Thedose of drug may be controlled by provision of a metered valve.

Alternatively the active ingredients may be provided in the form of adry powder, for example a powder mix of the compound in a suitablepowder base such as lactose, starch, starch derivatives such ashydroxypropylmethyl cellulose and polyvinylpyrrolidone (PVP).Conveniently the powder carrier will form a gel in the nasal cavity. Thepowder composition may be presented in unit dose form for example incapsules or cartridges of, e.g., gelatin, or blister packs from whichthe powder may be administered by means of an inhaler.

In compositions intended for administration to the respiratory tract,including intranasal compositions, the compound will generally have asmall particle size for example of the order of 5 microns or less. Sucha particle size may be obtained by means known in the art, for exampleby micronization.

When desired, compositions adapted to give sustained release of theactive ingredient may be employed.

The pharmaceutical preparations are preferably in unit dosage forms. Insuch form, the preparation is subdivided into unit doses containingappropriate quantities of the active component. The unit dosage form canbe a packaged preparation, the package containing discrete quantities ofpreparation, such as packaged tablets, capsules, and powders in vials orampoules. Also, the unit dosage form can be a capsule, tablet, cachet,or lozenge itself, or it can be the appropriate number of any of thesein packaged form.

In one embodiment, the invention provides tablets or capsules for oraladministration.

In another embodiment, the invention provides liquids for intravenousadministration and continuous infusion.

Further details on techniques for formulation and administration may befound in the latest edition of Remington's Pharmaceutical Sciences(Maack Publishing Co., Easton, Pa.).

The dose administered must of course be carefully adjusted to the age,weight and condition of the individual being treated, as well as theroute of administration, dosage form and regimen, and the resultdesired, and the exact dosage should of course be determined by thepractitioner.

The actual dosage depends on the nature and severity of the diseasebeing treated, and is within the discretion of the physician, and may bevaried by titration of the dosage to the particular circumstances ofthis invention to produce the desired therapeutic effect. However, it ispresently contemplated that pharmaceutical compositions containing offrom about 0.1 to about 500 mg of active ingredient of formula (I) perindividual dose, preferably of from about 1 to about 100 mg, mostpreferred of from about 1 to about 10 mg, are suitable for therapeutictreatments.

The active ingredient of formula (I) may be administered in one orseveral doses per day. A satisfactory result can, in certain instances,be obtained at a dosage as low as 0.1 μg/kg i.v. and 1 μg/kg p.o. Theupper limit of the dosage range is presently considered to be about 10mg/kg i.v. and 100 mg/kg p.o. Preferred ranges are from about 0.1 μg/kgto about 10 mg/kg/day i.v., and from about 1 μg/kg to about 100mg/kg/day p.o.

Methods of Therapy

In another aspect the invention provides a method for the treatment,prevention or alleviation of a disease or a disorder or a condition of aliving animal body, including a human, which disease, disorder orcondition is responsive to modulation of GABA_(A) receptors containingthe α5 subunit, and which method comprises administering to such aliving animal body, including a human, in need thereof an effectiveamount of the phenyl triazole derivative of formula (I) of theinvention, or a pharmaceutically acceptable salt thereof.

It is at present contemplated that suitable dosage ranges are 0.1 to1000 milligrams daily, 10-500 milligrams daily, and especially 30-100milligrams daily, dependent as usual upon the exact mode ofadministration, form in which administered, the indication toward whichthe administration is directed, the subject involved and the body weightof the subject involved, and further the preference and experience ofthe physician or veterinarian in charge.

EXAMPLES

The invention is further illustrated with reference to the followingexamples, which are not intended to be in any way limiting to the scopeof the invention as claimed.

Example 1 Preparative Example Preparation of1-{6-[5-(2-Fluoro-phenyl)-3-methyl-3H-[1,2,3]triazol-4-ylmethoxy]-pyridin-3-yl}-1H-imidazole-4-carbonitrile(Compound 7)

Preparation of 4-(2-fluorophenyl)-1-methyl-1H-1,2,3-triazole (Compound3)

To a pre cooled (−78° C., internal temp. −70° C.) solution ofdiisopropyl amine (193.13 g, 1899.04 mmol) in THF (1500 ml) undernitrogen atmosphere was added n-Butyllithium (759.617 ml, 1899.04 mmol,2.5 M solution in hexane) and stirred for 90 min. Then N,N-dimethylnitrous amide 2 (134.57 g, 1816.48 mmol) in THF (500 ml) was cannulatedportion wise during a period of 30 min. and stirred for 1 h. Then asolution of 2-Fluorobenzonitrile 1 (100.0 g, 825.671 mmol) in THF (500ml) was cannulated portion wise during a period of 30 min and stirred at−78° C. (internal temp. −70° C.) for 1 h. Then cooling bath was removedand stirred at room temperature for 2 h. The reaction was monitored byTLC and UPLC. The above reaction mass was slowly quenched with saturatedsolution of ammonium chloride (2000 ml) at room temperature and theaqueous layer was extracted with dichloromethane (5×2000 ml). Thecombined organic layer was dried over sodium sulphate, filtered andconcentrated to afford crude mass (170.0 g, 116.21% mass balance). Itwas purified by gravity column using 30% ethyl acetate in pet ether asan eluent to furnish desired product4-(2-fluorophenyl)-1-methyl-1H-1,2,3-triazole (64.52 g, 44.10% massbalance) as reddish gum. Then it was triturated with methyl tert-butylether (1000 ml) and hexane (500 ml), the supernant layer was decantedand the solid was dried to furnish desired product4-(2-fluorophenyl)-1-methyl-1H-1,2,3-triazole (32.9 g, 22.49%) asyellowish solid.

¹H NMR (400 MHz, CDCl₃): δ 8.30 (t, J=7.64 Hz, 1H), 7.94 (d, J=3.72 Hz,1H), 7.34-7.24 (m, 2H), 7.15 (t, J=6.72 Hz, 1H), 4.17 (s, 1H);MH⁺=178.1/179.2.

Preparation of4-(2-Fluorophenyl)-1-methyl-1H-1,2,3-triazole-5-carbaldehyde (Compound4)

To a pre cooled (−70° C. to −78° C.) solution of4-(2-fluorophenyl)-1-methyl-1H-1,2,3-triazole 3 (51 g, 287.84 mmol)under nitrogen atmosphere in THF (1200 ml) was added n-Butyllithium(138.16 ml, 345.41 mmol, 2.5M solution in hexane) and stirred for 2 h.Then DMF (1200 ml, 14794.844 mmol) was added and stirred at −78° C. for30 min. The reaction was monitored by TLC and UPLC. The reaction mixturewas slowly quenched with ice cold water (1000 ml) and the aqueous layerwas extracted with ethyl acetate (5×1000 ml). The combined organic layerwas dried over sodium sulphate, filtered and concentrated to affordcrude mass (50 g, 84.66% mass balance). It was purified by gravitycolumn using 20% ethyl acetate in pet ether as an eluent to afforddesired product4-(2-Fluorophenyl)-1-methyl-1H-1,2,3-triazole-5-carbaldehyde (40 g,67.72%) as reddish solid. Then it was triturated with methyl tert-butylether (1000 ml) and hexane (500 ml), the supernant layer was decantedand the solid was dried to furnish desired product4-(2-Fluorophenyl)-1-methyl-1H-1,2,3-triazole-5-carbaldehyde (32 g,54.18% yield) as white solid.

¹H NMR (400 MHz, CDCl₃): δ 10.00 (d, J=3.4 Hz, 1H), 7.80 (td, J=7.6 &1.6 Hz, 1H), 7.51 (td, J=7.6 & 0.8 Hz, 1H), 7.37-7.33 (m, 1H), 7.28 (t,J=9.88 Hz, 1H), 4.40 (s, 3H); MH⁺=206.1/207.1; IR: 1686.3 cm⁻¹.

Preparation of (4-(2-Fluorophenyl)-1-methyl-1H-1,2,3-triazole-5-yl)methanol (5)

To a stirred solution of4-(2-Fluorophenyl)-1-methyl-1H-1,2,3-triazole-5-carbaldehyde 4 (38 g,185.19 mmol) under nitrogen atmosphere in methanol (300 ml) was addedsodium borohydride (8.407 g, 222.23 mmol) in portion wise at 0° C. andthe reaction mass stirred for 20 min. The reaction was monitored by TLCand UPLC. The reaction mixture was quenched with water (500 ml) andconcentrated to remove methanol and water. Then it was extracted withethyl acetate (4×500 ml), combined organic layer was washed with brine(50 ml), dried over sodium sulphate, filtered and concentrated to affordcrude mass (34 g, 88.6% mass balance). The above solid was trituratedwith hexane (3×100 ml), the supernant layer was decanted and the solidwas dried to afford desired product(4-(2-Fluorophenyl)-1-methyl-1H-1,2,3-triazole-5-yl) methanol (31 g,80.77%) as off-white solid.

¹H NMR (400 MHz, CDCl₃): δ 7.67 (dt, J=7.60 & 1.76 Hz, 1H), 7.40-7.37(m, 1H), 7.26 (dt, J=7.50 & 1.00 Hz, 1H), 7.17 (t, J=8.32 Hz, 1H), 4.76(s, 2H), 4.717 (s, 3H), 2.60 (s, 1H, exchangeable with D₂O); UPLC (m/z):208 (MH⁺); HPLC Purity: 99.44%; IR: 3201.3 cm⁻¹; MP: 99.1-102.2° C.

Preparation of2-[5-(2-Fluoro-phenyl)-3-methyl-3H-[1,2,3]triazol-4-ylmethoxy]-5-iodo-pyridine(Compound 6)

To a suspension of NaH (0.73 g, 18.1 mmol, 60% in mineral oil) in DMF(10 ml) under N₂ atmosphere at 0° C. was added[5-(2-Fluoro-phenyl)-3-methyl-3H-[1,2,3]triazol-4-yl]-methanol (2.5 g,12.06 mmol) and stirred for 1 h. Then 2-chloro-5-iodopyridine (3.17 g,13.27 mmol) was added and reaction mixture was slowly warmed to roomtemperature and stirred for 4 h. The reaction was monitored by TLC. Thereaction mixture was quenched with ice-water, extracted withethylacetate (50 ml), washed with brine (10 ml), dried over Na₂SO₄ andconcentrated under reduced pressure to afford crude mass (4.4 g, 88.9%mass balance). It was triturated with hexane and the solid was filteredand dried under vacuum to furnish2-[5-(2-Fluoro-phenyl)-3-methyl-3H-[1,2,3]triazol-4-ylmethoxy]-5-iodo-pyridine(2.4 g, 48.48%) as yellow solid.

¹H NMR (400 MHz, DMSO-D₆): δ 8.28 (d, J=2.00 Hz, 1H), 8.00 (q_(ab),J=8.64 & 2.16 Hz, 1H), 7.58 (t, J=7.44 Hz, 1H), 7.49 (q, J=5.68 Hz, 1H),7.32 (q, J=7.32 Hz, 2H), 6.70 (d, J=8.68 Hz, 1H), 5.44 (s, 2H), 4.15 (s,3H).

Preparation of1-{6-[5-(2-Fluoro-phenyl)-3-methyl-3H-[1,2,3]triazol-4-ylmethoxy]-pyridin-3-yl}-1H-imidazole-4-carbonitrile(Compound 7)

The mixture of2-[5-(2-Fluoro-phenyl)-3-methyl-3H-[1,2,3]triazol-4-ylmethoxy]-5-iodo-pyridine(0.5 g, 1.22 mmol), 1H-imidazole-4-carbonitrile (0.170 g, 1.82 mmol),cesium carbonate (0.79 g, 2.43 mmol), copper(I)oxide (0.017 g, 0.122mmol), ferric acetylacetonate (0.129 g, 0.365 mmol) in DMF (10 ml) washeated at 90° C. for 20 h. The reaction was monitored by TLC and UPLC.The reaction mixture was concentrated under reduced pressure, water wasadded and extracted with ethylacetate (3×50 ml). The organic layer waswashed with brine (15 ml), dried over Na₂SO₄ and concentrated underreduced pressure to afford crude mass (500 mg, 109% mass balance). Itwas purified in grace column using 2% methanol in chloroform as aneluent to furnish desired1-{6-[5-(2-Fluoro-phenyl)-3-methyl-3H-[1,2,3]triazol-4-ylmethoxy]-pyridin-3-yl}-1H-imidazole-4-carbonitrile(0.180 g, 39.38%) as off-white solid.

¹H NMR (400 MHz, DMSO-D₆): δ 8.68 (d, J=1.16 Hz, 1H), 8.46 (d, J=2.8 Hz,1H), 8.42 (d, J=1.12 Hz, 1H), 8.06 (dd, J=8.88 & 2.8 Hz, 1H), 7.61 (dt,J=7.4 & 1.6 Hz, 1H), 7.52-7.48 (m, 1H), 7.35 (q, J=9.2 Hz, 2H), 7.05 (d,J=8.84 Hz, 1H), 5.53 (s, 2H), 4.18 (s, 3H). UPLC (m/z): 375/377 (MH⁺);HPLC purity: 96.96%; MP: 178.0-181.5° C.

Example 2 In vitro inhibition of ³H-flumazenil (³H-Ro 15-1788) bindingHEK cells expressing the human GABA_(A) α₅β₃*γ_(2S) receptor

The benzodiazepine modulator unit can selectively be labelled with theantagonist ³H-flumazenil.

The affinity of ³H-flumazenil for different subunit combinations havebeen reported to be 1.0 nM, 1.1 nM, 1.5 nM and 0.4 nM for α₁β₂γ₂,α₂β₂γ₂, α₃β₂γ₂, and α₅β₂γ₂ receptors, respectively, and 107 nM and 90 nMfor α₄β₂γ₂ and α₆β₂γ₂ receptors (see Sieghart; Pharmacol. Rev. 1995 47181-234).

The pharmacology of the mutated α₅β₃*γ_(2S) GABA_(A) receptor is similarto that of the wild type receptor with respect ³H-flumazenil binding.

Cell Cultures and Membrane Preparation

HEK-293 cell lines with stable expression of recombinant human GABA_(A)α₅β₂γ_(2S) receptors (plasmid H46/E9/B10) are seeded in T175 polystyreneflasks or roller bottles (1700 cm², Fisher Scientific CCI-431191), andcultured (37° C., 5% CO₂) in Dulbecco's Modified Eagle Medium (DMEM)with GlutaMAX™ supplemented with 10% fetal bovine serum and one or bothof the following antibiotics: hygromycin B (50 μg/ml; γ₂ subunit) orG418 (0.5 mg/ml; α₅ subunit).

When the cultures reach confluency, the DMEM is removed and the cellsare washed (10 ml for T175 flasks; 50 ml for roller bottles) once inDulbecco's Phosphate Buffered Saline (DPBS). Following addition of DPBSto the cultures (10 ml for T175 flasks; 100 ml for roller bottles) forapproximately 5 min cells are easily detached from the surface byshaking or tapping the flask gently. The cell suspension is transferredto Falcon tubes and centrifuged at 23,500×g for 10 min at 2° C. Thepellet is washed once in 15 ml Tris-citrate buffer (50 mM, pH 7.1) usingan Ultra-Turrax homogenizer and centrifuged at 2° C. for 10 min at27,000×g. The washed pellet is re-suspended in 15 ml Tris-citrate bufferand frozen at −80° C. until the day of the binding experiment.

Assay

On the day of the experiment the cell membrane preparation is thawed andcentrifuged at 2° C. for 10 min at 27,000×g. The pellet is re-suspended,using an Ultra-Turrax homogenizer in Tris-citrate buffer, to 15-50 μgprotein per assay and then used for binding assays.

Aliquots of 500 μl cell suspension are added to 25 μl of test compoundsolution and 25 μl of ³H-flumazenil (1 nM, final concentration), mixedand incubated for 40 min at 2° C. Non-specific binding is determinedusing clonazepam (1 μM, final concentration).

All dilutions of test compounds and incubation of assay are performed inglass vials/96-vial plates. Solutions of test compounds and³H-flumazenil are prepared 22× the desired final concentration.Compounds are dissolved in 100% DMSO (10 mM stock), diluted in 48%ethanol-water, and tested in triplicate in serial 1:3 or 1:10 dilutions.When screening large numbers of compounds only one concentration of eachcompound is tested in single wells. Reference compounds are not includedroutinely, but for each experiment performed total and non-specificbinding is compared to data obtained during validation of the assay.

Binding is either terminated by rapid filtration onto

1) Whatman GF/C glass fibre filters using a Brandel Cell harvester,followed by 5 washes with 1 ml ice-cold buffer or onto

2) UniFilter GF/C glass fibre filter plates using a Tomtec cellharvester, followed by washing with approximately 5 ml ice-cold buffer.

The amount of radioactivity on the filters is determined by conventionalliquid scintillation counting using a

1) Tri-Carb™ counter (PerkinElmer Life and Analytical Sciences) forseparate large filters or

2) Topcount™ counter (PerkinElmer Life and Analytical Sciences) for96-well filter plates. Specific binding is total binding minusnon-specific binding.

Calculations

25-75% inhibition of specific binding must be obtained beforecalculation of an IC₅₀ (the concentration (μM) of the test compoundwhich inhibits the specific binding of ³H-flumazenil by 50%).

The IC₅₀ value for a test compound is determined based on the equation:B=100−(100*C ^(n)/(IC₅₀ ^(n) +C ^(n)))

where B is the binding in percentage of total specific binding; C is theconcentration of test compound; and n is the Hill coefficient. Forscreening purposes n is set to 1. The IC₅₀ value is calculated from theconcentration response curves by the non-linear regression method usingthe curve-fitting program GraphPad Prism.

The Ki value for a test compound can be calculated from the IC₅₀ valueusing the equation by Cheng and Prusoff:K _(i)=IC₅₀/(1+L/K _(d))

where the K_(d) for ³H-flumazenil is 0.36 nM, and L is the measuredconcentration of ³H-flumazenil in the inhibition assay.

Test result from this experiment is shown in Table 1 below.

TABLE 1 In vitro inhibition of ³H-flumazenil Test compound K_(i) (μM)Compound 7 0.02

Example 3 Pharmaceutical Compositions

The phenyl triazole derivative of formula (I) of the invention may beput on any desirable form of composition, and may be dosed in anydesired amount. This example shows the preparation of a standard capsuleformulation.

Standard Capsule Formulation

Capsules containing 1 mg active pharmaceutical ingredient (API) offormula (I) per capsule are obtained using the following composition:

Amount Ingredient Function (mg/capsule) API Active ingredient 1 Starch500 Filler 117

The calculated amount of drug substance and filler corresponding to 1 mgof active drug substance and 117 mg of filler per capsule are weighedout and dry-mixed. The blend is subsequently filled into the calculatednumber of capsules (preferably size 4).

Example 4

FIG. 1 shows modulation of α₅β₂γ₂ GABA_(A) receptor currents by thecompound of formula (I) in Xenopus laevis oocytes. Modulatory efficacyof compound (1) (the compound of formula (I) as the free base) wasdetermined by techniques similar to those described in Mirza et al. (JPharmacol Exp Ther. 2008; 327:954-68). In brief, oocytes were injectedwith cRNA for human GABA_(A) receptor subunits α₅, β₂ and γ₂ in a 1:1:2ratio and modulatory efficacy was evaluated by co-applications with asubmaximal EC₅₋₂₀ GABA concentration (0.5 μM) termed GABA control. Thecompound was tested in five concentrations (3.16, 0.316, 0.0316, 0.00316and 0.000316 μM) on each oocyte starting with the lowest concentration.Background subtracted peak current amplitudes were normalized to therespective GABA control current, converted to % change anddepicted±S.E.M. as a function of increasing compound concentrations.Plotted datapoints were fitted to the empirical Hill equation usingnon-linear regression. 95% confidence intervals for maximal efficacy(Bottom) and potency (Log EC50) are derived from this fitting routine.

The invention claimed is:
 1. A phenyl triazole derivative which is1-[6-[[5-(2-fluorophenyl)-3-methyl-triazol-4-yl]methoxy]-3-pyridyl]imidazole-4-carbonitrile;or a pharmaceutically acceptable salt thereof.
 2. A pharmaceuticalcomposition, comprising a therapeutically effective amount of the phenyltriazole derivative of claim 1, or a pharmaceutically acceptable saltthereof, together with at least one pharmaceutically acceptable carrier,excipient or diluent.